It's more likely that your dealer lied to you about the firmware version, rather than the throttle went bad.
But if you have to buy a new throttle, try
@AltaWest, or
@ElectroBraap, or search the Classifieds, or post your own a Willing-to-Buy ad. OEM throttles are floating around, and I do not think anyone has broken one yet, many folks might want to sell them for the right price. If all fails, you can buy a new one from the manufacturer. Might have to move your harness with the connector over to it. All the ex-Alta folks would help you with which throttle model to buy. I wouldn't worry about the throttle until I check the firmware.